<!DOCTYPE html>

<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>小米 Pro 10</title>

        <style>

            body{
                margin: 0;
                padding: 0;
            }
            .wrapper{
                width: 100%;
                height: 100%;
                position: relative;
            }
            .header{
                width: 1226px;
                height: 80px;
                margin: 0 auto;
                position: relative;
            }
            .hover{
                height: 80px;
                width: 100px;
                text-align: center;
                align-items: center;
            }
            .link{
                height: 80px;
                width: 80px;
                line-height: 80px;
            }
            .info{
                height: 0px;
                width: 100%;
                background: #ff6700;
                transition: 0.5s;
            }
            .hover:hover  .info{
                height: 100px;
            }


        </style>

    </head>

    <body>

    <div class="wrapper">
        <div class="header">
            <li class="hover">
                <span class="link">小米手机</span>

                <div class="info">
                </div>
            </li>

        </div>

    </div>

    </body>
</html>